This invention relates to a multiple cassette record and/or playback apparatus and, more particularly, to an automatic cassette eject mechanism to be used with such apparatus, whereby a selected cassette can be removed from the apparatus almost immediately after processing.
Magnetic tape cassettes wherein a magnetic tape is stored in a self-contained cartridge are widely used in various record and/or playback devices, such as in home entertainment systems, data logging systems, dictation systems and the like. Such tape cassettes offer the advantages of greately simplifying the loading and unloading of tape by an operator, of protecting the tape during recording and playback operations and during handling of the tape, and of minimizing the bulk of the recording and playback devices used therewith. However, since the amount of tape that can be stored easily in a typical cartridge is rather constrained, there are finite limits on the amount of information that can be recorded thereon. In an attempt to increase such limitations of recorded information, some cassette manufacturers have attempted to increase the length of tape stored in a cassette. Nevertheless, in many applications, it is desirable to record and/or play back information substantially continuously for a length of time that exceeds even the capacity of these cassettes.
Accordingly, there have been proposals for automatic cassette-changing devices whereby a multiple of tape cassettes can be automatically loaded individually and successively onto a record/playback deck to permit an operator to record or reproduce substantial lengths of information. In one proposed automatic cassette changing device, described in U.S. Pat. No. 3,821,806, a plurality of cassettes is stored in drum-like configuration and retrieved individually to be loaded onto a record/playback deck and then returned to the storage drum. This proposed device requires a relatively complex mechanical structure for the retrieval, loading, unloading and return of cassettes.
In another proposed automatic cassette changer, such as described in U.S. Pat. No. 3,752,485, plural cassettes are stored in a magazine of a type that is commonly found in photographic slide projector apparatus. As the magazine is indexed, individual cassettes are sequentially "pushed" from their storage compartments by a pushing arm and loaded onto a record/playback deck. After information is recorded on or reproduced from the loaded cassette, it is returned to its storage compartment in the magazine by the pushing arm and the magazine then is indexed to enable the next cassette to be retrieved.
A similar magazine-type cassette-changer is described in U.S. Pat. No. 3,860,964. These type of cassette-changing devices require a relatively complex mechanical construction and, moreover, are subject to various malfunctions, such as cassette jams, during loading and unloading operations. Moreover, if used to record information thereon, it may be difficult to withdraw recorded cassettes from the magazine until the full complement of cassettes has been used.
In a further proposed automatic cassette-changer, such as described in U.S. Pat. No. 3,756,608, plural cassettes are stored in a magazine in stacked configuration, and individual cassettes are loaded onto a record/playback deck and thence into an output magazine, also in stacked configuration. As described in this patent, the record/playback deck is disposed beneath the input stack and a movable platform lowers a cassette from the input stack onto the deck. After a recording or playback operation, the platform is raised and a "pusher" pushes the cassette from the platform into the output magazine. The use of mechanical "pushers" is undesirable because of a susceptibility to jam the cassettes during a loading and/or unloading operation. Furthermore, since the next succeeding cassette cannot be loaded onto the deck until the immediately preceding cassette is fully unloaded by the mechanical "pusher", this automatic cassette-changer is relatively inefficient. That is, since this changer is not capable of loading a cassette simultaneously with unloading a cassette, a significant amount of time is required for a complete unloading/loading cycle.
In one contemplated use of an automatic cassette changer, such as in a central dictation system, many operators located at respective remote dictate stations will communicate selectively and individually with a central recorder with which the cassette changer is used. As messages are dictated and cassettes are used, or filled with dictation, the used cassettes are stored in, for example, an output magazine of the type described in aforementioned U. S. Pat. 3,756,608. In some operations, the information recorded on a particular cassette may be designated as "priority" information that should be transcribed or listened to as soon as possible. However, if this priority cassette is loaded into the output magazine in the usual manner, rapid recall of the recorded information is delayed. One proposed solution to this problem, as described in U. S. Pat. No. 3,756,608, is to move the priority cassette into position to be loaded into the output magazine, but the final "load" step is not performed. Thus, after the next cassette is used, this next cassette will be moved toward the position occupied by the priority cassette and will "push" the priority cassette into, for example, an output hopper. Hence, the priority cassette can be withdrawn from the apparatus sooner than if it had been loaded in the output magazine.
Unfortunately, with the mechanism of the type described in U.S. Pat. No. 3,756,608, the priority cassette cannot be removed, or ejected, from the apparatus until the next succeeding cassette is used. The delay in sufficiently using the next cassette can be many hours, or even days, depending upon the overall usage of the apparatus. Thus, the priority information cannot be retrieved promptly. On the other hand, if the cassette next succeeding the priority cassette is not used to record information, but merely is "pushed" through the apparatus, the waste of a cassette merely for the purpose of ejecting a priority cassette is inefficient and not satisfactory.